Apparatus for advancing unprintable negatives through photographic printers

ABSTRACT

Apparatus responsive to the detected density of a plurality of peripheral background areas of a negative and the central area of a negative determines whether the negative is suitable for producing an acceptable print and whether classification correction is necessary in printing the negative. Over-exposed or fogged negatives and under-exposed or blank negatives are detected by a comparison of the peripheral and central area density with reference densities to generate an unprintable negative signal. A splice signal is also generated upon the detection of a splice connecting negative strips. Apparatus responsive to the unprintable negative signal and the splice signal advances unprintable negatives or negatives otherwise unsuitable for producing acceptable prints and splices, respectively, through the printing station of the printer without printing the negative or the splice. However, if all negatives in a negative strip are determined to be unprintable, the last unprintable negative is printed so that an order sort mark may be placed on the print to keep the group of prints in each customer&#39;&#39;s order coordinated with its respective negative filmstrip. If the negative is determined to be printable, the densities of the central and peripheral areas of the negative are compared to each other in a predetermined manner to determine if the negative exhibits an unequal distribution in density indicating a subject failure. Apparatus is provided to activate classification correction factors provided on the printer in response to the classification of the negative.

United States Patent Rickard et al'. [4 1 Sept. 12, 1972 APPARATUS FORADVANCING rality of peripheral background areas of a negativeUNPRINTABLE NEGATIVES and the central area of a negative determineswhether THROUGH PHOTOGRAPH: the negative is suitable for producing anacceptable PRINTERS print and whether classification correction isnecessary in printing the negative. Over-exposed or fogged [72]Inventors: f Rlckardi William negatives and under-exposed or blanknegatives are Klem both of Rochester detected by a comparison of theperipheral and cen- 14650 tral area density with reference densities togenerate 73 Assignee; Eastman Kodak Company an unprintable negativesignal. A splice signal is also generated upon the detection of a spliceconnecting Filedi April 1971 negative strips. Apparatus responsive tothe unprinta- [21] Appl No; 133,649 ble negative signal and the splicesignal advances unprintable negatives or negatives otherwise unsuitablefor producing acceptable prints and splices, respec- [52] US. Cl...355/97, 355/68, 355/83, tively, through the printing station of theprinter /2 2 without printing the negative or the splice. However, if[51] Int. Cl. ..G03b 27/04 all negatives in a negative strip aredetermined to be [58] Field oi Search ....355/97, 83, 103, 68; 356/202,unprintable, the last unprintable negative is printed so 356/203 that anorder sort mark may be placed on the print to keep the group of printsin each customers order [56] References Cited coordinated with itsrespective negative filmstrip.

UNITED STATES 'PATENTS If the negative is determined to be printable,the densities of the central and peripheral areas of the nega- 3,l68,8602/1965 Clerk et al. ..355/l03 X tive are compared to each other in apredetermined 3,479,119 11/1969 Miller et al. ..355/83 X I PrimaryExaminer-Samuel S. Matthews Assistant Examiner-Richard L. MosesAttorney-W. H. J. Kline and Joseph F. Breimayer 57 ABSTRACT Apparatusresponsive to the detected density of a plumanner to determine if thenegative exhibits an unequal distribution in density indicating asubject failure. Apparatus is provided to activate classificationcorrection factors provided on the printer in response to theclassification of the negative.

24 Claims, 8 Drawing Figures g-IG l PRINTING I 32 STATION 4 Sheets-Sheet1 PR/ N TING STATION ROBERT K. R/CKARD WILLIAM C. KLEIN ATTORNEYSCROSS-REFERENCE TO RELATED APPLICATION Reference is made to commonlyassigned, copending U.S. application, Ser. No. 67,331, entitled MethodAnd Apparatus For Sensing Radiation Derived From Information BearingMedia, filed in the names of Robert W. Huboi, Osmond F. Palmer andEdward M. Waz on Aug.27, 1970.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to photographic apparatus, and more particularly to apparatusfor advancing unprintable photographic negatives or negatives otherwiseunsuitable for producing acceptable prints and filmstrip splices througha photographic printer without printing them and for classifying aprintable photographic negative in accordance with its densitymodulation.

2. Description of the Prior Art As is well-known in the prior art,machines conventionally referred to as printers or printing machines areused to project a light image of a photographic original upon asensitized sheet of photographic printing paper to produce a positiveprint from the photographic original or negative. Such, printers usuallycontain means for measuring the brightness of each photographic originaland for automatically controlling the exposure of the sheet ofphotographic paper accordingly. For example, subtractive color printersof the type shown in commonly assigned U.S. Pat. No. 3,184,307 includered, green and blue color sensitive monitors that are provided tomeasure the red, green and blue light in the printing beam transmittedby the original. The integrated transmittance measurements are convertedinto large area transmission density (LATD) signals that are applied totiming circuits which control the insertion of corresponding subtractivecolor filters into the printing beam to terminate the exposure of thephotographic print material to each respective color. Furthermore, theLATD measurement systems and subtractive color filters are normallyinterconnected so as to mix the transmission signals and thereby reducethe color correction level of the LATD measurement system. Photographicprinters operating under the principles of the LATD measurement systemnormally include variable color correction level adjustments which areset to maximize the number of color balanced prints obtainable from anaverage population of negatives.

Guided by the measurement of the total integrated transmittance of eachnegative by the LATD system, very satisfactory prints may be obtainedfrom a large number of negatives on the first printing. However, theaverage population of negatives submitted for printing contains asignificant number of negatives that are not printable that is, are notsuitable for producing acceptable prints, such as grossly over-exposed or fogged negatives and under-exposed or blank negatives which resultfrom errors in exposure or improper film handling. Furthermore, asignificant number of negatives may be unacceptable due to anabnormality in the illumination of the negative known in the art assubject failure. Two extreme, but frequently occurring, examples ofnegatives exhibiting subject failure are a single flash exposure of achild against a dark 5 background and another picture of a child againsta background of snow. It is not unreasonable to expect that the child,in both cases may require the same printing exposure. The integratedlight flux transmitted by the negative, as the LATD measuring photocellssee it, in the single flash picture, shows a very large amount of lighttransmitted by the very light area surrounding the child in thenegative. However, a very small amount of light is transmitted by thedense background area of the back-lit snow scene negative. When thetotal light transmittance of these two negatives is integrated, theeffect of the density of the background areas of each negative biasesthe LATD measurement resulting in under-exposed and over-exposed prints,respectively.

These problems are well-known and recognized in black and white andcolor printing. After some experience, a good printer operatorimmediately recognizes and bypasses unprintable negatives and comes torecognize a subject failure problem from inspection of the negatives,and corrects his exposure for subject failure as part of the firstprinting operation. In production type photofinisher printing, thiscorrection is known as subject classification and has been reduced, asan operation, to the simple pressing of a proper classification buttonprovided by the manufacturer of the printer which alters the exposuretime that would normally be determined by the LATD measurement system.

Despite this assessment of the negative by a skilled person, it is stillnecessary to view the resultant prints in order to eliminateunsatisfactory prints and to repeat the exposure of the correspondingnegatives at corrected exposure times. For this reason and in order toincrease the speed of the printing operation, many photofinishers haveresorted to the practice of setting the color correction to an optimumlevel and having the printer continuously print all negatives at thehighest attainable speed without inspection by an operator. Thereafter,unsatisfactory prints and their corresponding negatives are determinedby a print in spector who calculates, if the negative is printable, theproper subject classification. The subject classification may berecorded on the unsatisfactory print or elsewhere and reprinted by anoperator on a further printer.

The process outlined above is considerably inefficient in view of thenumber of unacceptable prints that are produced during the firstprinting operation. Many proposals have already been made to improve andcomplete the automation of the process of printing color negatives andto simplify the procedure. It has already been proposed for example toautomatically pick out the negatives that are unsuitable for printingand to omit these during first printing process. See for example U.S.Pat. No. 3,516,741 entitled Apparatus For Making Prints From ColorNegatives.

It has also been proposed in U.S. Pat. No. 3,537,790, entitled NegativeFeeder For Photographic Printer, to provide as an attachment, anautomatic negative feeder for advancing a continuous strip of negativespast an opening in the table of av standard printer including a viewingstation which allows the operator to view the film before it is printed,and to provide automatic means for inactivating the printer whenover-exposed or under-exposed prints are detected. In addition automaticmeans are included to sense a splice between adjacent strips of thefilmstrip and to place a mark on the photographic paper in the printerso that an end of order can be sensed by automatic equipment used tosever the pictures of each order.

Such apparatus known in the prior art does not provide for subjectclassification of printable photographic negatives, an operation whichhas normally required the skill and judgment of an operator viewing thenegative.

SUMMARY OF THE INVENTION Accordingly, it is an object of our inventionto increase the number of satisfactory prints produced by anoperatorless photographic printer.

Another object of our invention is to provide an operatorlessclassification of photographic negatives in accordance with the densitymodulation of the negative.

It is a further object of the invention to automatically classify anegative in accordance with its measured density variations and toprovide corresponding direction signals for the exposure control systemof a photographic printer.

It is still another object of the invention to determine if a negativeis unprintable and to advance unprintable negatives through the printingstation of the printer without printing them.

Another object of the invention is to detect splices connecting negativefilmstrips and to prevent the exposure in the printing station of suchsplices.

It is still another object of this invention to print one negative ororiginal that is unsuitable for producing an acceptable print betweensplices whenever all the negatives between the splices are suitable forproducing acceptable prints.

A preferred embodiment of the present invention is disclosed inconnection with a photographic printer which comprises first and secondradiation sensitive means responsive to the radiation transmittance offirst and second respective areas of an information bearing medium, suchas a photographic original, for producing corresponding first and secondsignals, each of the first and second signals having an amplitudedependent upon the radiation transmittance (corresponding to anddependent upon density modification of a photographic original) of eachrespective areas of said information bearing medium. Means responsive tofirst and second reference signals having first and second referenceamplitudes and to the amplitudes of the first and second signals providefirst and second unprintable signals. More particularly, the first andsecond reference amplitudes are indicative of the maximum and minimumtransmittances, respectively, of a photographic original that can besuccessfully printed to produce an acceptable print. The firstunprintable signal is produced when the amplitudes of the first andsecond signals exceed the first reference amplitude, and the secondunprintable signal is produced when the second reference amplitudeexceeds the amplitudes of the first and second signals. Means respond tothe first and second unprintable signals to prevent the printing of thephotographic original.

Further apparatus responsive to the relative amplitudes of the firstsignals produce classification signals for controlling the exposure ofphotographic originals that are determined to be printable. Apparatusresponsive to splices, and the absence of any photographic original thatis suitable for producing an acceptable print in a photographic originalfilmstrip provide for the printing of at least one photographic originalin such as filmstrip to separate customer order prints.

The method of operation of the apparatus of the preferred embodiment ofthe invention in the modes to be described hereinafter advantageouslyreduces the number of faulty prints produced by an operatorlessphotographic printer.

Other objects and advantages of the invention will become more apparentfrom the following description taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the detailed description of thepreferred embodiment of the invention presented below, reference is madeto the accompanying drawings, in which:

FIG. 1 is a perspective view showing the location of splice detectionand negative density determining photosensitive devices located withrespect to a negative filmstrip;

FIG. 2 is a schematic illustration of an electrical circuit fordetecting an unprintable negative;

FIG. 3 is a schematic illustration of an electrical circuit forautomatically advancing an unprintable negative through the printingstation of a photographic printer;

FIG. 4 is a schematic illustration of an electrical circuit fordetecting splices connecting negative filmstrips; and

FIG. 5 is a schematic illustration of an electrical circuit forclassifying a printable negative.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawingsand first to FIG. 1 there is shown a perspective view of an array ofphotosensitive devices situated with respect to a negative filmstrip 10to produce a plurality of density signals and a first and second splicedetection signal in accordance with the teachings of the presentinvention. The negative filmstrip 10 advances left to right in thedirection of the arrow 12 from a supply reel (not shown) through theprinting station 14 of a printer and to a take-up reel (not shown). Themodel 2620 color printer manufactured and sold by Eastman Kodak Companyconstitutes one type of printer that is provided with apparatus forintermittently advancing and printing negative filmstrips of a customersorder that have been spliced together and wound upon a supply reel afterprocessing of the filmstrips. Such a printer is normally provided with aviewing station at which an operator inspects the negative to beprinted, determines if it is printable, and classifies the negative. Theprinter is provided with a series of classification correction factorswhich may be selectively employed to modify the LATD measurement outputsignal to correct for subject failures perceived by the printeroperator. Closing the switch contact to call for one of these factorsalso initiates the printing of the negative. It will be understood thatthe terms printable and unprintable refer to conditions of the detecteddensities in each of the measured areas of the negative that indicatethat the negative is suitable or unsuitable, respectively, for producingan acceptable print. A negative determined to be unprintable because itis too under-exposed or blank or over-exposed or fogged, may be printedin the printer but would result in an unacceptable print.

In accordance with the teachings of the present invention, the operationof an existing printer may be modified by the addition of the apparatusshown in FIG. 1 and the circuitry of FIGS. 2-5 to eliminate thenecessity of an operator for the machine. In FIG. 1, a first and asecond light source 16 and 18, respectively, are arranged to directlight through the negative filmstrip and upon a plurality ofphotosensitive devices arranged in a predetermined array in acompartmented housing 20. The compartmented housing and the first andsecond light sources 16 and 18 are located in a negative examinationstation at least one negative distance away from the printing station 14of the printer.

The compartmented housing 20 contains five cellular chambers 22, 24, 26,28 and 30, that have a combined dimension along the negative filmstripl0 equivalent to the dimensions of each negative 32 of the filmstrip 10.The chambers 22, 24, 26 and 28 of the housing 20 are arranged so thatlight from light source 16 passes through respective peripheral areas22a, 24a, 26a and 28a of the negative 32 and onto respectivephotosensitive devices 22b, 24b, 26b (not shown) and 28b. Thus the lighttransmitted by four peripheral areas of the negative 32 is measured bythe photosensitive devices 22b, 24b, 26b and 28b.

The fifth chamber of the housing 20 contains a fifth photosensitivedevice 30b (not shown) which is responsive to light from light source 16transmitted by the central area 300 of the negative 32. Electricalconductors 34, 36, 38, 40 and 42 are connected to the photosensitivedevice 22b, 24b, 26b, 28b and 3012, respectively.

The negative filmstrip 10 consists of a number of individual customerorders spliced together as shown, for example, at 44 by an opaque splice46 which extends almost completely across the width of the negativefilmstrip 10. The housing 20 contains a sixth chamber 48 having a shapecorresponding to the perimeter 48a of the splice 46 and located withinone negative frame distance from the first five chambers in the housing20. Located within the sixth chamber 48 is a first splice detectingphotosensitive device 48b that is sensitive to the light from lightsource 18 transmitted by the negative filmstrip 10 to produce a firstsignal on the conductor 50. A second splice detecting photosensor 48c islocated within the first chamber 22 and is responsive to light fromlight source 16 transmitted by the negative filmstrip 10 to produce asecond signal on conductor 52.

The splice 46 is opaque, and, in the position of the negative filmstrip10 shown in FIG. 1, absorbs light emitted by light source 18 andprevents it from falling into chamber 48 and upon the first splicedetecting photosensitive device 48b. Therefore, in the presence of asplice 46, the light detecting photosensitive device 48b does notproduce an output signal on the conductor 50. As the negative filmstrip10 advances in the direction of the arrow 12, the splice 46 will alsoabsorb light emitted by light source 16 and prevent light from fallingupon the second splice detecting photosensitive device 48c. Thus, thesplice 46 is detected by two separate splice detecting photosensitivedevices that produce two separate splice signals on conductors 50 and52.

Thus the negative 32 is uniformly illuminated by the light source 16,and the photosensitive devices in each of the five chambers measure thetransmission of each respective area of the negative covering eachrespective chamber. The particular arrangement of the chambers and theirtotal number are selected so that negatives exhibiting a subject failuredue to backlighting or front-lighting of the scene may be readilyascertained by a comparison of the negative transmittances of each area.If only a single photosensitive device looking at the entire area of thenegative were employed or a number of separate photosensitive deviceslooking at the entire area of the negative were employed, unprintablenegative detection and subject classification of such a subject failurenegative would be difficult.

Referring now to FIG. 2 there is shown a circuit for the unprintablenegative detector that responds to the output signals of thephotosensitive devices of FIG. 1 to determine if a negative isprintable. The photosensitive devices 22b, 24b, 26b, 28b and 30b areelectrically connected in parallel between a source of positive voltage+V and a source of negative voltage V through resistors 54, 56, 58, 60and 62 and are respectively connected to the output conductors 34, 36,38, 40 and 42. The output conductors 34, 36, 38, 40 and 42 are connectedin parallel to the anodes of gating diodes 64 and the cathodes of gatingdiodes 66, respectively. The cathodes of gating diodes 64 and the anodesof diodes 66 are commonly connected to the base electrodes oftransistors 68 and 70. The NPN transistor 68 is connected at itscollector electrode to a source of positive voltage +V and at itsemitter electrode to one terminal of a resistor 72, the other terminalof which is connected to a negative voltage source V. Similarly, thecollector terminal of PNP transistor 70 is connected to a negativevoltage source V, and the emitter terminal of transistor 70 is connectedto one terminal of resistor 74, the other terminal of which is connectedto a positive voltage source V.

As shown in FIG. 1 each of the photosensitive devices 22b, 24b, 26b, 28band 30b are responsive to light transmitted by predetermined areas ofthe negative 32. As shown in FIG. 2 the voltage on output conductors 34,36, 38, 40 and 42, respectively, is directly dependent upon the amountof light striking each respective photosensitive device. These voltagelevels are transmitted by the gating diodes 64 and 66 to the baseelectrodes of the transistors 68 and 70, respectively. The outputvoltage developed at the emitter terminal of the transistor 68, whichoperates as an emitterfollower, corresponds to the highest voltage ofthe voltage levels on the conductors 34, 36, 38, 40 and 42. This voltagesignal developed at the emitter terminal of transistor 68 is conductedby resistor 76 to the negative input terminal 78 of amplifier 80. Asource of positive voltage +V is also applied by variable resistor 82 tothe negative input terminal 78 of the differential amplifier 80. Afeedback network consisting of resistors 84 and 86 connect the positiveinput terminal 88 of the amplifier 80 with the output terminal 90 ofamplifier 80. The positive feedback stabilizes the operation of theamplifier 80, and isolation diode 92 is connected at its anode terminalto the output terminal 90 and at its cathode terminal to the commonoutput terminal 94.

The resistor 76 and the variable resistor 82 act as b, voltage dividerwith respect to the positive voltage source +V and the output signaldeveloped at the emitter terminal of transistor 68. As statedhereinbefore the transistor 68 operates as an emitter-follower amplifierthe output of which corresponds in magnitude to the least negativesignal developed by the photosensitive devices 22b, 24b, 26b, 28b and30b. If a low amount of light is transmitted by the negative 32 upon allof the photosensitive devices 22b, 24b, 26b, 28b and 30b, the outputsignal of the emitter-follower amplifier is relatively negative. I

The resistor 76, the variable resistor 82, the positive voltage source+V and the amplifier 80 operate as a voltage comparator which produces apositive output signal at output terminal 90 when the magnitude of theleast negative signal developed by the photosensitive devices is lessthan the positive voltage provided by the setting of the variableresistor 82. The development of a positive voltage output signal atoutput terminal 90 indicates that the negative being examined is sodense that it is unprintable due to gross over-exposure or fogging ofthe negative. The adjustment of the variable resistor 82 determines thelevel at which the negative is considered unprintable.

Similarly the output signal developed at the emitter terminal of PNPtransistor 70 is conducted by resistor 96 to the positive input terminal98 of a second amplifier 100. A negative voltage source -V is alsoapplied by a variable resistor 102 to the positive input terminal 98.Resistors 104 and 106 are also provided to stabilize the operation ofthe amplifier 100. A further isolation diode 108 is connected at itsanode terminal to the output terminal 110 of amplifier 100 and at itscathode terminal to the common output terminal94 of the unprintablenegative detecting circuit.

The transistor 70 also operates as an emitter-follower that produces anoutput signal at its emitter terminal that corresponds to the leastpositive of the voltages generated by the photosensitive devices 22b,24b, 26b, 28b and 30b. This output signal is compared to the referencesignal provided by the negative voltage source V and the variableresistor 102. When the negative being examined is highly transmissive oflight through all areas of the negative, the voltage signals developedat the cathodes of gating diodes 66 are positive in sign and relativelylarge. If all the photosensitive devices are sufficiently illuminated,the output signal of transistor 70 is sufficiently positive with respectto the negative reference signal level to provide a positive voltagesignal at the input terminal 98 of the amplifier 100. Amplifier 100responds to a positive input voltage signal to produce a positive outputsignal at its output terminal 110. When such a positive output signal isdeveloped, the negative being examined is considered to be unprintabledue to a blank negative or a grossly underexposed negative. The level ofunder-exposure at which an output signal is developed at output terminalmay be controlled by the setting of the variable resistor 102.

The output signals of the two comparator circuits are transmitted tocommon point 94 by the isolation diodes 92 and 108. To summarize theoperation of the circuit, fogged or over-exposed negatives cause theproduction of a positive output signal at the output terminal 90, andblank or under-exposed negatives cause the production of a positiveoutput signal at output terminal 110. Printable negatives cause neitheroutput signal. Furthermore all five photosensitive devices 22b, 24b,26b, 28b and 30b have to be relatively non-conductive before an outputsignal can be developed at the point 90 or have to be highly conductivebefore the output signal is produced at the output terminal 110. If anyone of the five photosensitive devices generates a voltage level fallingbetween the voltage level set by the variable resistors 82 and 102(indicating some discernible subject matter on the negative frame),neither output signals can be generated. The provision of the fivephotosensitive devices operating independently in parallel insures thatprintable subject failure negatives can be distinguished fromunprintable negatives.

The common output terminal 94 of the unprintable negative detectioncircuit of FIG. 2 corresponds to point 94 of FIG. 3. FIG. 3 is aschematic illustration of the printer sequencing circuits of aphotographic printer including the feature of an automatic unprintablenegative advance circuit employed in the practice of the presentinvention. All of the elements of the circuit of FIG. 3 are electricallyconnected in parallel between a conductor 112 connected to a V supplyand a ground return conductor 114. Each element will be described interms of its operation in conjunction with the elements of FIGS. 1 and2. The common output terminal 94 of the unprintable negative detectioncircuit of FIG. 2 is connected at the junction of two resistors 116 and118 which are connected by conductor 120 and diode 122 between thecommon lines 112 and 114. The base electrode of a transistor 124 isconnected to the junction between the resistor 118 and the anode ofdiode 122. The emitter of transistor 124 is connected to commonconductor 114, and the collector of transistor 124 is connected to oneterminal of a PRINTABLE NEGATIVE relay 126, the other terminal of whichis connected to the conductor 120. Normally, PRINTABLE NEGATIVE relay126 is energized through the continuous conduction of transistor 124which is biased on by resistor 116. However, when a positive unprintablenegative signal is generated by the unprintable negative detectorcircuit of FIG. 2, the transistor 124 is rendered nonconductive, and thePRINTABLE NEGATIVE relay 126 is deenergized.

Referring now to the operation of the circuit of FIG. 3, the filmstrip10 of FIG. 1 is advanced through the printing station 14 by depressingthe FILM JOG button 128 which energized the film advance mechanism 130and disengages the film drive clutch 131 of a conven' tional printer,such as the Model 2620 printer. As the negative frame underconsideration advances to the negative examination station, the FILMADVANCE relay 132 is energized through printer sequencing circuits ofthe printer which causes the normally open relay contacts 1320 to closeand the normally closed relay contacts 132b and 1320 to open. When thenormally open relay contacts 132a close, the capacitor 134 charges tothe negative voltage supply V. At the end of the advance of the negativefilrnstrip, the film drive clutch 131 engages, normally open relaycontacts 132a reopen and normally closed relay contacts 132b and 1320reclose. Capacitor 134 discharges through normally closed relay contacts132b, and READ OUT relay 136. When READ OUT relay 136 is energized,normally open relay contacts 136a and l36b are closed. Since, in theabsence of an unprintable negative signal, PRINTABLE NEGATIVE relay 126is energized, normally closed relay contacts 126a are open and normallyopen relay contacts 126b are closed.

Since normally open relay contacts 1364 are closed but normally closedrelay contacts 126a are open, no current is allowed to flow in conductor138, and FILM 'JOG relay 140 remains deenergized. However, sincenormally open relay contacts 126b are closed, the closure of normallyopen relay contacts 136b closes an energization circuit 142 across thePRINT button 144 of the printer, and the exposure memory circuit 146 ofa conventional printer, such as the aforementioned Model 2620 printer,is connected to the supply voltage V. Upon the energization of theexposure memory circuit 146, the exposure memory receives and stores asubject classification input signal on one of the three subjectclassification input terminals 148, 150 and 152 described in connectionwith FIG. 5. After storage of the subject classification input signal,the exposure memory circuit 146 advances the negative frame from thenegative examination station into the printing station 14 of thephotographic printer and initiates an exposure. Upon the advancement ofthe negative filrnstrip, the film advance relay 132 is again energized,and the cycle explained hereinabove repeats for so long as anunprintable negative signal is not generated by the unprintable negativedetector circuit of FIG. 2.

When, however, an unprintable negative signal is generated at terminal94, the transistor 124 is reversebiased and ceases to conduct current,and relay 126 is deenergized. When relay 126 is deenergized, normallyclosed relay contacts 126a remain closed, and normally open relaycontacts 126k remain open. The sequence of operation diflers to theextent that when READ OUT relay 136 is energized by the discharge ofcapacitor 134 after the cessation of film advance and the movement ofthe unprintable negative frame into the printing station 14,normally-open relay contacts 136a close and complete the circuit fromthe common conductor 112 through the normally closed relay contacts126a, conductor 138, FILM JOG relay 140 and common conductor 114, thusenergizing FILM JOG relay 140.

While READ OUT relay 136 is still energized, FILM JOG relay 140 becomesenergized as described above, and normally open relay contacts 140a areclosed, thus insuring that the FILM JOG relay 140 remains energizedafter normally open relay contacts 136a reopen upon the completedischarge of capacitor 134. The energization of FILM JOG relay 140 alsocloses normally open relay contacts 140!) which bypass the FILM JOGbutton 128 to conduct current to the film advance mechanism 130. Thefilm advance mechanism 130 ad vances the negative frame found to beunprintable through the printing station 14 of the printer. While thenegative filrnstrip is advancing, film advance relay 132 is energized,and normally closed relay contacts 132a reopen to deenergize FILM JOGrelay 140. After the film advance is completed, film advance relay 132deenergizes and READ OUT relay 136 becomes energized again upon thedischarge of capacitor 134. If, again, the negative is found to beunprintable this cycle repeats until a printable negative is detected.For as long as no printable photographic negatives are detected, thenormally open relay contacts 126b will remain open to prevent theenergization of the exposure memory circuit 146 .and the exposure of thenegative in the printing station.

In the event that all of the negative frames of a particular customer'sorder are found to be unprintable by the unprintable negative detectorof FIG. 2, it is still necessary to make at least one print in orderthat order sort and customer identification marks can be placed upon theprint to keep successive customer order prints correlated with thecustomer order negatives. Norm ally the order sort mark is concurrentlyprinted on the edge of the paper during the exposure of the firstprintable negative frame of each negative filrnstrip. The splicedetection circuit of FIG. 4 accomplishes this function and also preventsthe erroneous printing of the spliced area of the negative filrnstrip ofFIG. 1.

Referring now to FIG. 4, there is shown a splice detection circuitincorporating the first place detecting photosensitive device 48b andthe second splice detecting photosensitive device 48c. The splicedetecting photosensitive devices 48b and 480 are connected in seriesrelation with resistors 154 and 156, respectively, and connected inparallel between a positive voltage source +V and a negative voltagesource V. The output conductors 50 and 52 are connected to the resistorand the common point 158 of the splice detection circuits, respectively,through the splice detector amplifiers 157 and 159. The resistor 160 isconnected to the base electrode of a transistor 162, and a clamp diode164 connects the base electrode of the transistor 162 to the commonconductor 166 of the ground return.

The common point 158 is connected by normally closed PRINTABLE NEGATIVErelay contacts 126c to a terminal of SPLICE relay 172, the otherterminal of which is connected to the common conductor 166. Connectedbetween the common point 158 and the supply conductor are the normallyopen relay contacts 172a. Also connected between the common point 158and the common conductor 166 are the series connected capacitor 174 andSPLICE MEMORY CAN- CEL relay 176, and ORDER SORT PRINT relay 178 isconnected between the common point 158 and the collector of transistor162. Normally open relay contacts 178a are also connected to thecollector of transistor 162 and to the common conductor 166. A furtherset of normally open relay contacts 178!) are connected across the PRINTbutton 144 of FIG. 3.

Referring now to the operation of the splice detector circuit of FIG. 4,it will be recalled from the discussion of FIG. 1 that the splicedetecting photosensitive devices 48b and 48c were normally renderedconductive by predetermined wavelengths of light, which for example maybe infrared radiation emitted by the first and second light sources 16and 18 and transmitted by the negative filmstrip 10. Thus, as shown inthe circuit of FIG. 4, when the splice detecting photosensitive devices48b and 480 are rendered conductive, the voltage signals supplied by thesplice detector amplifiers 157 and 159 to the base of transistor 162 andthe common terminal 158, respectively, are positive, and no currentflows through the relays 172, 176 or 178. However, the splice detectingphotosensitive devices 48b and 48c cease to conduct current when thesplice 46 of FIG. 1 passes between them and the light sources 16 and 18.

A frame with a splice applied will be detected by the unprintablenegative detector as a printable negative since it is too narrow tocover all of the chambers of the housing 20. It is necessary thereforeto cancel the normal print signal which would be generated, as describedhereinbefore, by the circuit of FIG. 3. This cancellation isaccomplished as the splice 46 advances over the splice detectingphotosensitive device 48c. The sudden change in the polarity of thevoltage signal from positive to negative on conductor 158 is capacitycoupled by the capacitor 174 to the SPLICE MEMORY CANCEL relay 176 whichis energized thereby. The momentary energization of the SPLICE MEMORYCANCEL relay 176 opens the normallyclosed relay contacts 176a todisconnect the exposure memory circuit 146 of FIG. 3 from the groundreturn conductor 114. As a result no exposure is initiated by theexposure memory circuit 146 after the film stops.

In the event that no printable negative exists in a customers order, aprint must be made of a frame between splices in order to keep eachcustomers order separate. The SPLICE relay 172 is also energized duringthe period that the SPLICE MEMORY CANCEL relay 176 is energized. TheSPLICE relay 172, when energized, closes the normally open relaycontacts 172a in order to energize itself after the splice 46 moves pastthe splice detecting photosensitive device 480. Splice relay 172 willremain energized until a printable negative is detected whereupon relay126 of FIG. 3 is energized, and normally closed relay contacts 126c areopen. However, if a second splice 46 is detected by the first splicedetecting photosensitive device 48b before a printable negative hasreleased SPLICE relay 172, normally open relay contacts 172a will remainclosed. Upon the detection of a second splice 46 by the first splicedetecting photosensitive device 48b, the output signal to resistor 160abruptly changes from a positive voltage to a negative voltage. Thenegative voltage signal is transmitted by resistor 160 to the base oftransistor 162 which is rendered conductive thereby. Upon the conductionof transistor 162, the ORDER SORT PRINT relay 178 is energized. TheORDER SORT PRINT relay 178 closes normally open relay contacts 178a toenergize itself upon the continued movement of the second splice 46.

Referring back to FIG. 3, the normally open relay contacts 178b of theORDER SORT PRINT relay 178 are closed, and a print is made by theenergization of the exposure memory circuit 146 upon the advance of thelast unprintable negative of the customer order into the printingstation 14 of the photographic printer. Simultaneously, the exposurememory circuit 146 provides an order sort mark on the print in order tokeep successive customer print orders separate.

Thus apparatus has been shown for detecting unprintable photographicnegatives and advancing such unprintable photographic negatives througha photographic printer without printing them, and further apparatus hasbeen shown that responds to the situation where all negative frames of acustomers order are unprintable for making at least one print therefromin order to keep subsequent customer print orders separate.

Referring now to FIG. 5 there is shown a further circuit that isresponsive to a predetermined comparison of the negative transmittancesof the five areas 22a, 24a, 26a, 28a and 30a of the negative frame 32for detecting abnormal density variations in the negative andprovidingclassification correction signals for printing subject failurenegatives. As noted hereinbefore, subject failure negatives usually fallinto two categories, that is negatives carry back-lit scenes orflash-lit scenes. These two categories may be recognized by anabnormally high negative density in the upper peripheral (sky) area orthe central and the lower peripheral (flash subject) areas,respectively, of the negative. The abnormal density of a back-litnegative is compensated for during printing by shortening the totalexposure time that would normally be provided by the LATD exposurecontrol system. Conversely, the abnormal density of a flash-lit negativeis compensated for by lengthening the total exposure time of thenegative provided by the LATD exposure control system. Normally theoperator of a printer examines the negative to be printed and classifiesit as a normal or subject failure negative, and he presses theappropriate classification button provided on the console of theprinter. The depression of the classification button introduces thecorresponding correction factor into the LATD monitoring circuitry ofthe printer. It has been found desirable to automatically classify thenegative and to correct for abnormal density variations in the negative.This has been accomplished, as describedin the aforementioned commonlyassigned, copending US. application, Ser. No. 67,331 by separatelymeasuring the negative densities in the upper peripheral area, the lowerperipheral area and the central area of a negative and combining thesedensities in a predetermined manner in order to produce the appropriatecorrection factor.

Referring now to FIG. 5 there is shown a negative classification circuitfor use with the photosensitive devices 22b, 24b, 26b, 28b and 30b ofFIGS. 1 and 2. The conductors 34, 36, 38, 40 and 42 are connected to thebase electrodes of respective transistor 180, 182, 184, 186 and 188,respectively, the collector electrodes of which are commonly connectedto a positive voltage source +V and the emitters of which are commonlyconnected through respective resistors 190, 192, 194, 196 and 198 to anegative voltage source V. Output conductors 200, 202, 204, 206 and 208are respectively connected to the emitter terminals of transistors 180,182, 184, 186 and 188.

Thus the transistors 180, 182, 184, 186 and 188 operate as theemitter-followers that produce an output signal on the respective outputconductors that correspond in amplitude and polarity to the positivevoltage signal having an amplitude falling within the range of +V to Vdeveloped on the input conductors 34, 36, 38, 40 and 42, respectively.These input voltages are developed in the same manner as described inthe discussion of the operation of the photosensitive devices 22b, 24b,26b, 28b and 30b of FIG. 2.

The output conductor 206 is connected by resistors 210 and 212 to thepositive input terminal of differential amplifier 214 and the negativeinput terminal of differential amplifier 216. The output conductors 200,202, 204 and 208 are connected in summing relation through resistors218, 220, 222 and 224 to the negative input terminal of differentialamplifier 214 and in summing relation to the positive input terminal ofdifferential amplifier 216 through resistors 226, 228, 230 and 232. Thenegative input terminal of differential amplifier 214 is also connectedto a negative voltage source V through a variable resistor 324 thatconstitutes the BUTTON adjustment. Similarly the positive input terminalof differential amplifier 216 is connected to a positive voltage source+V to a variable resistor 236 that constitutes the BUTTON adjustment.The Button adjustment and BUTTON adjustments are provided so that thesensitivity of the classification circuit may be adjusted to the pointat which the maximum number of acceptable prints are produced by theclassification correction circuit.

The output terminal of the differential amplifier 214 is coupled byresistor 238 and diode 240 to the base electrode of switching transistor242. The emitter electrode of switching transistor 242 is grounded, andthe collector electrode is coupled through BUTTON relay 246 to anegative voltage source-V. A diode 244 is connected across the coil ofrelay 246.

Similarly the output terminal of differential amplifiers 216 is coupledby a resistor 248 and diode 250 to the base electrode of transistor 252.The emitter electrode of transistor 252 is connected to groundpotential, and the collector electrode is connected by l BUTTON relay256 to a negative voltage source V. A diode 254 is connected across thecoil of relay 256.

Associated with the BUTTON relay 246 are normally open relay contacts2460 that connect (when closed by energization of BUTTON relay 246) anegative voltage source V through the normally closed contacts 256a tothe BUTTON input conductor 152. Associated with the BUTTON relay 256 arethe normally open relay contacts 256b that connect (when closed byenergization of BUTTON relay 256) the negative voltage source V to theBUTTON input conductor 148. The normally closed relay contacts 246b and256a are series connected between the negative voltage source -V nd thenormal (N) BUTTON input conductor 150. The BUTTON input conductor 148,the (N) BUTTON input conductor 150 and the BUTTON input conductor 152are connected to the N and input terminals of the exposure memorycircuit 146 of FIG. 3. In the practice of the invention, these relaycontacts may be connected in the manner shown in FIG. 5 across theBUTTON, (N) BUTTON and BUTTON contacts on the console of a photographicprinter.

Referring now to the operation of the negative classification circuit ofFIG. 5, it will be notedthat normally the transistors 242 and 252 arenonconductive and the BUTTON relay 246 and the BUTTON relay 256 are notenergized. Therefore, the negative voltage source -V is normallyconnected to the (N) BUTTON input conductor by the normally closed relaycontacts 246b and 256a.

However, when the voltage developed at the positive input terminal ofthe differential amplifier 214 is more negative than the average of thevoltages applied at the negative input terminal, a negative voltage isdeveloped at the output terminal of the differential amplifier 214 andthe transistor 242 is rendered conductive. The conduction of transistor242 energizes the BUTTON relay 246, causing the normally open relaycontacts 246:; to close and the normally closed relay contacts 246b toopen. Therefore, the negative voltage-V is diverted to the BUTTONconductor 152.

Similarly, a negative output signal is developed at the output terminalof differential amplifier 216 when the average of the voltagesignals atthe positive input terminal of the differential amplifier 216 is lessnegative than the voltage signal applied at the negative input terminal.The transistor 252 is rendered conductive by the negative output signalthus energizing the BUT- TON relay 256. The energization of the BUTTONrelay 256 closes the normally open relay contacts 256b, thus energizingthe BUTTON input conductor 148.

Referring back to FIG. 1 it will be noted that the area 28a of thenegative 32 constitutes a portion of the upper peripheral area of thenegative scene and the photosensitive device 28b is responsive to thetransmissivity of this upper area of the negative scene. Similarly theother photosensitive devices respond to the transmissivity of the otherrespective areas of the scene carried by the negative 32. When thetransmissivity of the area 28a of the negative 32 is a certain amountlower than the average transmissivities of the remaining areas of thenegative 32, it can be assumed that the scene carried by the negative 32is back-lit, for example, by a bright sky. The output signal developedby the photosensitive device 28b in the circuit of FIG. 3 is applied byconductor 40 to the base electrode of transistor 186 of FIG. 5. When asstated, the transmissivity of the area 28a is relatively low, thevoltage developed on conductor 40 is relatively large and nega-- tive.The emitter-follower transistor 186 responds to this voltage signal todevelop a negative voltage signal on the output conductor 206 that isapplied to the plus input terminal of the differential amplifier 214 andthe minus input terminal of the differential amplifier 216. Similarlythe signal developed by the remaining photosensitive devices on theoutput conductors 200, 202, 204 and 208 are averaged at the negativeinput terminal of the differential amplifier 214 and the positive inputterminal of the differential amplifier 216. When the magnitude of thesignal developed on the output conductor 206 is more negative than theaverage magnitude of the signals developed on the output conductors 200,202, 204 and 208 and the BUTTON adjustment, the differential amplifier214 produces a negative output signal that, as described hereinbefore,renders transistor 242 conductive and energizes BUTTON relay 246. Inthis manner, the

negative is classified as a back-lit scene, and a proper negativecorrection factor is introduced into the LATD measurement system toshorten the total exposure time of the negative.

Similarly when the average transmissivity of the areas 22a, 24a, 26a and30a is a certain amount less than the transmissivity of the area 28a thenegative probably is carrying a front-lit scene, such as a flashpicture. This imbalance is characterized by the fact that the average ofthe output signals developed on the output conductors 200, 202, 204 and208 be less than the magnitude of the signal developed on the outputconductor 206, and the differential amplifier 216 responds to thisimbalance to produce a negative output signal. The negative outputsignal, as stated hereinbefore, renders transistor 252 conductive andenergizes the BUTTON relay 256 which energizes the BUT- TON conductor148. Thus the total exposure time for a front-lit scene is increased bythe addition of a positive correction factor to the LATD exposurecontrol system.

The circuit of FIG. constitutes but one example of the combinations ofparticular areas of the negative 32 that is effective to determine thatthe scene carried by the negative is a normally illuminated scene, aback-lit scene or a front-lit scene and to provide necessary correctionfor the classified scene. It will be apparent that other combinations ofpredetermined areas of the negative 32 may be made in order to practicethe present invention. For example, the housing of FIG. 1 may beprovided with any number of chambers and respective photosensitivedevices that are responsive to the transmissivity of respective areas ofthe negative 32. It is also apparent that the solid state photosensitivearray described in the aforementioned commonly assigned, copending U.S.application, Ser. No. 67,331 may be substituted for the photosensitivedevices 22a, 24a, 26a, 28a and 30a of the present invention. Appropriatecircuit modifications may be made to the negative classification circuitof FIG. 5 and the unprintable negative detection circuit of FIG. 2.

The invention has been described in detail with particular reference tothe preferred embodiment thereof, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

We claim:

1. Apparatus for performing an operation relative to a section of anelongated medium located in an operating station, said apparatuscomprising:

a. means for detecting a first predetermined condition of each sectionof the medium and for generating a first signal in response to thedetected first condition;

b. means for detecting a second predetermined condition of each sectionof the medium and for generating a second signal in response to thedetected second condition;

c. means for repetitively advancing each section of the elongated mediumto the operating station;

d. means responsive to the advancement of each section to the operatingstation and to the generation of the first signal for performing theoperation relative to the section of the elongated medium advanced tothe operating station;

e. means responsive to the advancement of each section of the elongatedmedium to the operating station and to the presence of the second signalfor continuing the advancement of the section 5 through the operatingstation; and

f. means responsive to the advancement of all sections of said elongatedmedium through the operating station in the presence of the secondsignal for performing the operation relative to at least one section ofthe elongated medium.

2. The apparatus of claim I wherein the elongated medium comprises aplurality of strips having leading, intermediate and trailing sections,wherein the strips are attached together at each end of the leading andtrailing sections of adjacent strips, and wherein said means responsiveto the advancement of the elongated medium in the presence of the secondsignal further comprises means responsive to the advancement of the 20leading and all intermediate sections of the strip through the operatingstation in the presence of the second signal for advancing the trailingsection of the strip into the operating station and performing theoperation relative to the trailing section of the strip.

3. The apparatus of claim 1 wherein the elongated medium comprises aplurality of strips having leading, intermediate and trailing sections,wherein the strips are attached together at each end of the leading andtrailing sections of adjacent strips, and wherein said 30 meansresponsive to the advancement of the elongated medium in the presence ofthe second signal further comprises:

a. means for detecting the attached ends of the strips and generatingthird signals in response thereto; and

b. means responsive to the advancement of the leading and allintermediate sections of the strip through the operating station in thepresence of the second signal and responsive to the third signal foradvancing the trailing section of the strip into the operating stationand performing the operation relative to the trailing section of thestrip.

4. Apparatus for printing at least one original of a photographicoriginal filmstrip comprising originals that are unsuitable for printingby exposure to a source of radiation, said apparatus comprising:

a. first means for detecting the radiation transmittance level of eachphotographic original and for generating an unprin'table original signalin response to a predetermined radiation transmittance level thatindicates that the original is unsuitable for producing an acceptableprint; and

b. second means responsive to the unprintable original signal beinggenerated by said first means with respect to every photographicoriginal of the photographic original filmstrip for printing at leastone photographic original unsuitable for producing an acceptable print.

5. In a photographic printer, wherein each original of the photographicoriginal filmstrip may be printed in an exposure station of the printer,apparatus for printing at least one original in a photographic originalfilmstrip comprising originals that are unsuitable for producing anacceptable print, said apparatus comprising:

a. means for detecting printable originals of a photographic originalfilmstrip that are suitable for producing an acceptable print andprinting the detected printable originals in the exposure station of theprinter;

b. means for detecting originals of a photographic original filmstripthat are unsuitable for producing an acceptable print and for preventingthe printing of the detected unsuitable originals in the exposurestation of the printer; and

c. means responsive to the absence of a printable original in aphotographic original filmstrip for printing at least one original thatis unsuitable for producing an acceptable print.

6. In a photographic printer, wherein developed photographic originalfilmstrips are attached together at leading and trailing ends thereofand each original of the photographic original filmstrips may besuccessively printed on photosensitive print material in the exposurestation of the printer, apparatus for printing at least one original ina photographic original filmstrip comprising originals detected asunsuitable for producing an acceptable print, said apparatus comprising:

a. means for detecting a first condition of each original indicatingthat such original is suitable for producing an acceptable print and forgenerating a first signal in response to the detected first condition;

b. means for detecting a second condition of each original indicatingthat such original is unsuitable for producing an acceptable print andfor generating a second signal in response to the detected secondcondition;

c. means for successively advancing each original of the photographicoriginal filmstrips to the exposure station of the printer;

(1. means responsive to the advancement of each original to the exposurestation and to the generation of the first signal with respect to theadvanced original for printing the advanced original;

e. means responsive to the advancement of each original to the exposurestation and to the generation of the second signal with respect to theadvanced original for preventing the printing of the original that isunsuitable for producing an acceptable print and for activating saidadvancing means; and

f. means responsive to the advancement of every original in aphotographic original filmstrip through the exposure station of theprinter in the absence of the first signal for printing at least oneoriginal that is unsuitable for producing an acceptable print.

. The apparatus of claim 6 wherein:

. the originals that are unsuitable for producing an acceptable printcomprise over-exposed or fogged or under-exposed or blank photographicoriginals;

. the photographic original filmstrips comprise leading, intermediateand trailing originals; and

c. said means for printing at least one original that is unsuitable forproducing an acceptable pring further comprises:

1. means responsive to the advancement of the attached leading ends ofsuccessive photographic original filmstrips to the exposure station fordetecting the attached leading ends and generating a third signal inresponse thereto;

2. means for detecting the attached trailing ends of successivephotographic original filmstrips as the trailing original of arespective photographic original filmstrip is advanced to the exposurestation and generating a fourth signal in response thereto;

3. means disposable in first and second states in response to the firstand third signals, respectively; and

4. means responsive to the fourth signal and the disposition of saidsecond means in said second state for printing the trailing originaladvanced to the exposure station.

8. In a photographic printer, wherein developed photographic originalfilmstrips comprising leading, intermediate and trailing originals areattached together at leading and trailing ends thereof by splices ateach end adjacent to leading and trailing originals of respectivefilmstrips, apparatus for printing, in an exposure station of theprinter, at least one original in a filmstrip wherein all of theleading, intermediate and trailing, originals are unsuitable forproducing acceptable prints, said apparatus comprising:

a. means for detecting a first condition of each original indicatingthat such original is suitable for producing an acceptable print and forgenerating a first signal in response to the detected first condition;

b. means for detecting a second condition of each original indicatingthat such original is unsuitable for producing an acceptable print andfor generating a second signal in response to the detected secondcondition;

c. means for advancing each original and the splices attachingsuccessive filmstrips to the exposure station of the printer;

. means located with respect to the exposure station of the printer fordetecting splices upon the advancement of the trailing original into theprinting station and for generating a third signal in response to thedetected splice;

e. means responsive to the advancement of a splice into the exposurestation and to the third signal for advancing the spliced ends ofsuccessive photographic original filmstrips, through the exposurestation, without printing the splice;

f. means responsive to the advancement of each original into theexposure station and to the first signal for printing the advancedoriginal;

g. means responsive to the advancement of each original into theexposure station and to the second signal for preventing the printing ofthe advanced original; and

. means responsive to the advancement of the leading and allintermediate originals through the exposure station of the printer inthe presence of the second signal and responsive to the third signal forprinting the trailing original in the exposure station.

. The apparatus of claim 6 wherein:

. the originals that are unsuitable for producing an acceptable printcomprise over-exposed or fogged or under-exposed or blank photographicoriginals;

. the photographic original filmstrips comprise leading, intermediateand trailing originals; and

c. said means for printing at least one original that is 11. A method ofprinting each original of a photounsuitable for producing an acceptableprint graphic original filmstrip, said method comprising the furthercomprises: steps of:

1. means responsive to the advancement of the ata. detecting apredetermined condition of each tached leading ends of successivephotographic original filmstrips to the exposure station for detectingthe attached leading ends and generating photographic original todetermine if the photographic original is suitable for producing anacceptable print;

a third signal in response thereto;

2. means for detecting the attached trailing ends of successivephotographic original filmstrips as 1 the trailing original of arespective photographic original filmstrip is advanced to the exposurestation and generating a fourth signal in response thereto;

3. means disposable in first and second states in response to the firstand third signals, respectively; and

4. means responsive to the fourth signal and the disposition of saidsecond means in said second state for printing the trailing originaladvanced to the exposure station.

10. A method of photographic printing, wherein photographic originalfilmstrips, consisting of leading, intermediate and trailing originals,are attached together by splices and advanced through an exposurestation, said method comprising the steps of:

a. directing radiation through each photographic original;

b. sensing the intensity of the radiation transmitted by each original;

c. comparing the sensed radiation intensity level transmitted by theoriginal with reference radiation intensity levels;

(1. advancing originals exhibiting radiation trans- 3 mittance levelsthat are excessively high or excessively low in comparison to thereference radiation intensity levels through the exposure station of thephotographic printer, without printing such originals;

e. advancing to the exposure station and printing originals exhibitingradiation transmittance levels that are acceptable in comparison withthe reference radiation intensity levels;

f. detecting splices attaching photographic original filmstrips upon theadvancement of the splices into the exposure station and producing afirst signal in response thereto;

g. applying the first signal to a switching element norb. printingphotographic originals determined to be suitable for producing anacceptable print; and

c. printing at least one photographic original when every photographicoriginal of the photographic original filmstrip is determined to beunsuitable for producing an acceptable print.

1 12. In a photographic printing process wherein developed photographicoriginal filmstrips, consisting of leading, intermediate and trailingoriginals, are attached by splices and intermittently advanced throughan exposure station of a photographic printer, a

20 method of advancing under-exposed or blank and overexposed or fogged,photographic originals through said exposure station, said methodcomprising the steps of:

a. controlling the exposure of printable photographic originals in saidexposure station in accordance with the exposure level of thephotographic originals;

b. advancing, without printing under-exposed or blank and over-exposedor fogged photographic originals through said exposure station of saidphotographic printer; and

c. exposing at least one photographic original frame in a photographicoriginal filmstrip comprising under-exposed or blank and over-exposed orfogged photographic originals.

the trailing photographic original in a photographic original filmstripcomprising under-exposed or blank and over-exposed or foggedphotographic originals.

40 14. In a photographic printer, apparatus for preventing the exposureof a photographic original exhibiting an excessively high or excessivelylow transmittance to radiation, said apparatus comprising:

a. means for directing radiation through said photographic original;

b. first and second photosensitive means responsive to the intensity ofradiation transmitted by first and second areas of said photographicoriginal for producing first and second signals;

13. In the method of claim 12 the step of exposing many disposed in afirst State and disposable in a 0. means for providing a first referencesignal having second state in response to the first signal;

h. producing a second signal in response to the printing of printable,leading, intermediate and trailing originals;

i. applying the second signal to said switching element to dispose saidswitching element in said normal first state;

j. detecting splices attaching photographic original filmstrips upon theadvancement of the trailing photographic original into the exposurestation and generating a third signal in response thereto; and

k. printing the trailing original in response tothe second state of saidswitching element and the third signal so that at least one original ina photographic original filmstrip consisting of unprintable originals isprinted.

a maximum level indicative of the maximum transmittance of aphotographic original that can be successfully printed;

. means for providing a second reference signal having a minimum levelindicative of the minimum transmittance of a photographic original thatcan be successfully printed;

. means responsive to the first reference signal and the first andsecond signals for producing a first unprintable original signal whenthe levels of the first and second signals exceed the maximum level ofthe first reference signal;

. means responsive to the second reference signal and the first andsecond signals for producing a second unprintable original signal whensaid minimum level of the second reference signal exceeds the level ofthe first and second signals; and

g. means responsive to the first and second unprintable original signalsfor preventing the printing of said photographic original.

15. The apparatus of claim 14 wherein said first reference signalproviding means further comprises means for varying the maximum level ofthe first reference signal and said second reference signal providingmeans further comprises means for varying the minimum level of thesecond reference signal.

16, The apparatus of claim 14 wherein said first and secondphotosensitive means further comprises:

a. first and second photosensitive elements each having first and secondterminals, said first terminals being commonly connected to a firstvoltage source, first and second resistance elements, each respectivelyconnecting said second terminal to a second voltage source, each of saidphotosensitive elements responding to radiation transmitted by eachrespective area of said photographic original to produce the firstsignal and the second signal at the respective second terminals of saidfirst and second photosensitive elements;

b. first means connected to said second terminals of said first andsecond photosensitive elements and responsive to the first and secondsignals for producing a first output signal having a levelrepresentative of the maximum level of the first and second signals; and

c. second means connected to said second terminals of said first andsecond elements and responsive to the first and second signals forproducing a second output signal having a level representative of theminimum level of the first and second signals.

17. The apparatus of claim 16 wherein said first unprintable originalsignal producing means is responsive to the first output signal and thefirst reference signal and wherein said second unprintable originalsignal producing means is responsive to the second output signal and thesecond reference signal.

18. In a photographic printer, wherein successive photographic originalfilmstrips are attached together by splices, apparatus for preventingthe exposure of said splices and of unprintable photographic originalsexhibiting an excessively high or excessively low transmittance toradiation, said apparatus comprising:

a. means for directing radiation through the photographic originals;

b. first and second photosensitive means responsive to the intensity ofradiation transmitted by first and second respective areas of saidphotographic original for producing first and second signals havinglevels dependent upon the radiation intensities transmitted by saidfirst and second areas;

c. means for providing a first reference signal having a maximum levelindicative of the maximum transmittance of a photographic original thatcan be successfully printed;

. means for providing a second reference signal having a minimum levelindicative of the minimum transmittance of a photographic original thatcan be successfully printed;

e. means responsive to the first reference signal and the first andsecond signals for producing a first unprintable original signal whenthe levels of the first and second signals exceed the maximum level ofthe first reference signal;

f. means responsive to the second reference signal and the first andsecond signals for producing a second unprintable original signal whensaid minimum level of the second reference signal exceeds the levels ofthe first and second signals;

g. means responsive to the first and second unprintable original signalfor preventing the printing of said photographic original;

. third photosensitive means located with respect to said radiationtransmitting means and said photographic original filmstrip forproducing a splice signal when a splice attaching successivephotographic original filmstrips prevents the transmission of radiationthrough said photographic original filmstrip and upon said secondphotosensitive means; and

i. means responsive to said splice signal for preventing the printing ofthe splice areas of said attached successive photographic originalfilmstrips.

19. The apparatus of claim 18 wherein said third photosensitive means isresponsive to a predetermined radiation spectrum of the radiationtransmitting means and wherein said splice comprises means forpreventing the transmission of said predetermined spectrum of radiationto said third radiation sensitive means.

20. In a photographic printer, apparatus for controlling the exposure ofa photographic original exhibiting an imbalance in density modulationbetween first and second areas of the photographic original and forpreventing the exposure of a photographic original exhibiting anexcessively high or excessively low transmittance to radiation in boththe first and the second areas, said apparatus comprising:

a. means for directing radiation through said photographic original;

b. first and second photosensitive means responsive to the intensity ofradiation transmitted by first and second respective areas of saidphotographic original for producing first and second signals havinglevels dependent upon the density modulation of each respective area ofsaid photographic original;

c. means for producing a first reference signal having a maximum levelindicative of the maximum transmittance of a photographic original thatcan be successfully printed;

d. means for producing a second reference signal having a minimum levelindicative of the minimum transmittance of a photographic original thatcan be successfully printed;

e. means responsive to the first reference signal and the first andsecond signals for producing a first unprintable original signal whenthe levels of both the first and the second signal exceed the maximumlevel of the first reference signal;

f. means responsive to the second reference signal and the first andsecond signals for producing a second unprintable original signal whensaid minimum level of the second reference signal exceeds the levels ofboth the first and the second signal;

g. means responsive to the first and second unprintable original signalfor preventing the printing of said photographic original; and

h. means responsive to the absence of the first and second unprintableoriginal signals and responsive to an imbalance in the amplitudes of thefirst and a. first means for producing a first exposure corsecondsignals for producing an exposure correction signal when the level ofthe first signal exrection signal. ceeds the level of the second signal;21. The apparatus of claim 10 wherein the exposure b. second means forproducing a second exposure correction signal producing means furthercomprises: correction signal when the level of the second a. first meansfor producing a first correction signal signal exceeds the level of thefirst signal; and

when the level of the first signal exceeds the level c. third means forproducing a third exposure corof the second signal; rection signal whenthe levels of the first and b. second means for producing a secondcorrection second signals are approximately equal.

signal when the level of the second signal exceeds 24. A method ofphotographic printing, wherein the level of the first signal; andphotographic original filmstrips are attached together c. third meansfor producing a third correction signal by splices and advanced throughan exposure station,

when the levels of the first and second signals are said methodcomprising the steps of:

approximately equal. a. directing radiation through first and secondareas 22. In a photographic printer, apparatus for providof eachphotographic original; ing an exposure correction signal for aphotographic b. sensing the intensity of the radiation transmittedoriginal exhibiting an imbalance in density modulation by said first andsecond areas of the photographic in first and second areas of thephotographic original, original; said apparatus comprising: c. comparingthe sensed radiation intensity levels a. means for directing radiationthrough said phototransmitted by said first and second areas withgraphic original; reference radiation intensitglevels;

b. first and second photosensitive means responsive d anclng origma sexhi iting radiation transto the intensity of radiation transmitted byfirst and mttance leYelS f P first and Second areas f the secondrespective areas of said photographic photographic original frames thatare excessively original for producing first and second signals each orf m companson. to the having a level dependent upon the density modu1areference radiation lntensity levels through the extion of eachrespective area of said photographic 9 Sumo F photograph'c punterwlthout original; printing such original frames;

c. means responsive to the amplitude of said first and detectfng Sphcesattachmg photographlc ongma said second signal for providing anunprintable 3O filmSmPs; photographic original signal when said levelsinadVFmCmg dfatected Sphce? thrfmgh P dicate that both the first andsecond areas of the of Sam photographic punter wlthout prmt'photographic original are unprintable; mg sphcfad areas;

(1. means responsive to the unprintable photographic cofnParmg the,radlanon mummy levels of the original signal for preventing theexposure of said radlanon f by the first photographic original in saidphotographic printer; and Provldmg an exposure correcnon Slgnal m andresponse to the degree of difference between the e. means operative inthe absence of an unprintable radian)? mtenFlty levels;

' photographic original signal and responsive to the afivancmg PrmtaPlepht,graph1c ong mals levels of said first and second signals forproviding 40 Sand exposure stanon of Sam photograph1c punter; anexposure correction signal dependent upon the and degree of imbalance inthe levels of the first and CQHFYOHmg exposure of a photograph"; SecondSignals original frame in accordance with the exposure 23. The apparatusof claim 22 wherein said exposure correcnon correction signal providingmeans further comprises:

I 1 mm 0m CERTIFICATE OF CORRECTION Pazentbw; 3,690,765 4 Dated October27, 1972 Invmnmr(s) Robert K. Rickard and William C. Klein It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Front page, Column 2, last line, after the abstract, "8"

(Drawing Figures) should read --5 (Drawing Figures.

Column 17, line 61, "pring" should be pr1nt--;

Column 23, line 4, "10" should be --20--.

Signed and sealed this Zhth day of April 1973.

(SEAL) Attest:

ROBERT GOTTSCHALK Commissioner of Patents EDWARD M. FLETCHER, JR.Attesting Officer HQERIIHFLCATE 0F CORRECTION Patent No. 3,690,765 DatedOctober 27, 1972 Inventor(s) Robert K. Rickard and William C. Klein Itis certified that error appears in the above-identified patent and thatsaid Letters Patent are vhereby corrected as shown below:

Front page, Columh 2, last line after the abstract, "8"

( Drawing Figures) should read --5- (Drawing Figures.

Columh l7 line 61, f'pring" should be "print- Column 23, line 4, "10'should be --20--.

Signed and sealed this 2 +th day or April 1973.

(SEAL) Attest:

EDWARD M. FLETCHER, JR. I ROBERT GOTTSCHALK Attesting OfficerCommissioner of Patents

1. Apparatus for performing an operation relative to a section of anelongated medium located in an operating station, said apparatuscomprising: a. means for detecting a first predetermined condition ofeach section of the medium and for generating a first signal in responseto the detected first condition; b. means for detecting a secondpredetermined condition of each section of the medium and for generatinga second signal in response to the detected second condition; c. meansfor repetitively advancing each section of the elongated medium to theoperating station; d. means responsive to the advancement of eachsection to the operating station and to the generation of the firstsignal for performing the operation relative to the section of theelongated medium advanced to the operating station; e. means responsiveto the advancement of each section of the elongated medium to theoperating station and to the presence of the second signal forcontinuing the advancement of the section through the operating station;and f. means responsive to the advancement of all sections of saidelongated medium through the operating station in the presence of thesecond signal for performing the operation relative to at least onesection of the elongated medium.
 2. The apparatus of claim 1 wherein theelongated medium comprises a plurality of strips having leading,intermediate and trailing sections, wherein the strips are attachedtogether at each end of the leading and trailing sections of adjacentstrips, and wherein said means responsive to the advancement of theelongated medium in the presence of the second signal further comprisesmeans responsive to the advancement of the leading and all intermediatesections of the strip through the operating station in the presence ofthe second signal for advancing the trailing section of the strip intothe operating station and performing the operation relative to thetrailing section of the strip.
 2. means for detecting the attachedtrailing ends of successive photographic original filmstrips as thetrailing original of a respective photographic original filmstrip isadvanced to the exposure station and generating a fourth signal inresponse thereto;
 2. means for detecting the attached trailing ends ofsuccessive photographic original filmstrips as the trailing original ofa respective photographic original filmstrip is advanced to the exposurestation and generating a fourth signal in response thereto;
 3. meansdisposable in first and second states in response to the first and thirdsignals, respectively; and
 3. means disposable in first and secondstates in response to the first and third signals, respectively; and 3.The apparatus of claim 1 wherein the elongated medium comprises aplurality of strips having leading, intermediate and trailing sections,wherein the strips are attached together at each end of the leading andtrailing sections of adjacent strips, and wherein said means responsiveto the advancement of the elongated medium in the presence of the secondsignal further comprises: a. means for detecting the attached ends ofthe strips and generating third signals in response thereto; and b.means responsive to the advancement of the leading and all intermediatesections of the strip through the operating station in the presence ofthe second signal and responsive to the third signal for advancing thetrailing section of the strip into the operating station and performingthe operation relative to the trailing section of the strip. 4.Apparatus for printing at least one original of a photographic originalfilmstrip comprising originals that are unsuitable for printing byexposure to a source of radiation, said apparatus comprising: a. firstmeans for detecting the radiation transmittance level of eachphotographic original and for generating an unprintable original signalin response to a predetermined radiation transmittance level thatindicates that the original is unsuitable for producing an acceptableprint; and b. second means responsive to the unprintable original signalbeing generated by said first means with respect to every photographicoriginal of the photographic original filmstrip for printing at leastone photographic original unsuitable for producing an acceptable prinT.4. means responsive to the fourth signal and the disposition of saidsecond means in said second state for printing the trailing originaladvanced to the Exposure station.
 4. means responsive to the fourthsignal and the disposition of said second means in said second state forprinting the trailing original advanced to the exposure station.
 5. In aphotographic printer, wherein each original of the photographic originalfilmstrip may be printed in an exposure station of the printer,apparatus for printing at least one original in a photographic originalfilmstrip comprising originals that are unsuitable for producing anacceptable print, said apparatus comprising: a. means for detectingprintable originals of a photographic original filmstrip that aresuitable for producing an acceptable print and printing the detectedprintable originals in the exposure station of the printer; b. means fordetecting originals of a photographic original filmstrip that areunsuitable for producing an acceptable print and for preventing theprinting of the detected unsuitable originals in the exposure station ofthe printer; and c. means responsive to the absence of a printableoriginal in a photographic original filmstrip for printing at least oneoriginal that is unsuitable for producing an acceptable print.
 6. In aphotographic printer, wherein developed photographic original filmstripsare attached together at leading and trailing ends thereof and eachoriginal of the photographic original filmstrips may be successivelyprinted on photosensitive print material in the exposure station of theprinter, apparatus for printing at least one original in a photographicoriginal filmstrip comprising originals detected as unsuitable forproducing an acceptable print, said apparatus comprising: a. means fordetecting a first condition of each original indicating that suchoriginal is suitable for producing an acceptable print and forgenerating a first signal in response to the detected first condition;b. means for detecting a second condition of each original indicatingthat such original is unsuitable for producing an acceptable print andfor generating a second signal in response to the detected secondcondition; c. means for successively advancing each original of thephotographic original filmstrips to the exposure station of the printer;d. means responsive to the advancement of each original to the exposurestation and to the generation of the first signal with respect to theadvanced original for printing the advanced original; e. meansresponsive to the advancement of each original to the exposure stationand to the generation of the second signal with respect to the advancedoriginal for preventing the printing of the original that is unsuitablefor producing an acceptable print and for activating said advancingmeans; and f. means responsive to the advancement of every original in aphotographic original filmstrip through the exposure station of theprinter in the absence of the first signal for printing at least oneoriginal that is unsuitable for producing an acceptable print.
 7. Theapparatus of claim 6 wherein: a. the originals that are unsuitable forproducing an acceptable print comprise over-exposed or fogged orunder-exposed or blank photographic originals; b. the photographicoriginal filmstrips comprise leading, intermediate and trailingoriginals; and c. said means for printing at least one original that isunsuitable for producing an acceptable pring further comprises:
 8. In aphotographic printer, wherein developed photographic original filmstripscomprising leading, intermediate and trailing originals are attachedtogether at leading and trailing ends thereof by splices at each endadjacent to leading and trailing originals of respective filmstrips,apparatus for printing, in an exposure station of the printer, at leastone original in a filmstrip wherein all of the leading, intermediate andtrailing, originals are unsuitable for producing acceptable prints, saidapparatus comprising: a. means for detecting a first condition of eachoriginal indicating that such original is suitable for producing anacceptable print and for generating a first signal in response to thedetected first condition; b. means for detecting a second condition ofeach original indicating that such original is unsuitable for producingan acceptable print and for generating a second signal in response tothe detected second condition; c. means for advancing each original andthe splices attaching successive filmstrips to the exposure station ofthe printer; d. means located with respect to the exposure station ofthe printer for detecting splices upon the advancement of the trailingoriginal into the printing station and for generating a third signal inresponse to the detected splice; e. means responsive to the advancementof a splice into the exposure station and to the third signal foradvancing the spliced ends of successive photographic originalfilmstrips, through the exposure station, without printing the splice;f. means responsive to the advancement of each original into theexposure station and to the first signal for printing the advancedoriginal; g. means responsive to the advancement of each original intothe exposure station and to the second signal for preventing theprinting of the advanced original; and h. means responsive to theadvancement of the leading and all intermediate originals through theexposure station of the printer in the presence of the second signal andresponsive to the third signal for printing the trailing original in theexposure station.
 9. The apparatus of claim 6 wherein: a. the originalsthat are unsuitable for producing an acceptable print compriseover-exposed or fogged or under-exposed or blank photographic originals;b. the photographic original filmstrips comprise leading, intermediateand trailing originals; and c. said means for printing at least oneoriginal that is unsuitable for producing an acceptable print furthercomprises:
 10. A method of photographic printing, wherein photographicoriginal filmstrips, consisting of leading, intermediate and trailingoriginals, are attached together by splices and advanced through anexposure station, said method comprising the steps of: a. directingradiation through each photographic original; b. sensing the intensityof the radiation transmitted by each original; c. comparing the sensedradiation intensity level transmitted by the original with referenceradiation intensity levels; d. advancing originals exhibiting radiationtransmittance levels that are excessively high or excessivEly low incomparison to the reference radiation intensity levels through theexposure station of the photographic printer, without printing suchoriginals; e. advancing to the exposure station and printing originalsexhibiting radiation transmittance levels that are acceptable incomparison with the reference radiation intensity levels; f. detectingsplices attaching photographic original filmstrips upon the advancementof the splices into the exposure station and producing a first signal inresponse thereto; g. applying the first signal to a switching elementnormally disposed in a first state and disposable in a second state inresponse to the first signal; h. producing a second signal in responseto the printing of printable, leading, intermediate and trailingoriginals; i. applying the second signal to said switching element todispose said switching element in said normal first state; j. detectingsplices attaching photographic original filmstrips upon the advancementof the trailing photographic original into the exposure station andgenerating a third signal in response thereto; and k. printing thetrailing original in response to the second state of said switchingelement and the third signal so that at least one original in aphotographic original filmstrip consisting of unprintable originals isprinted.
 11. A method of printing each original of a photographicoriginal filmstrip, said method comprising the steps of: a. detecting apredetermined condition of each photographic original to determine ifthe photographic original is suitable for producing an acceptable print;b. printing photographic originals determined to be suitable forproducing an acceptable print; and c. printing at least one photographicoriginal when every photographic original of the photographic originalfilmstrip is determined to be unsuitable for producing an acceptableprint.
 12. In a photographic printing process wherein developedphotographic original filmstrips, consisting of leading, intermediateand trailing originals, are attached by splices and intermittentlyadvanced through an exposure station of a photographic printer, a methodof advancing under-exposed or blank and over-exposed or fogged,photographic originals through said exposure station, said methodcomprising the steps of: a. controlling the exposure of printablephotographic originals in said exposure station in accordance with theexposure level of the photographic originals; b. advancing, withoutprinting under-exposed or blank and over-exposed or fogged photographicoriginals through said exposure station of said photographic printer;and c. exposing at least one photographic original frame in aphotographic original filmstrip comprising under-exposed or blank andover-exposed or fogged photographic originals.
 13. In the method ofclaim 12 the step of exposing the trailing photographic original in aphotographic original filmstrip comprising under-exposed or blank andover-exposed or fogged photographic originals.
 14. In a photographicprinter, apparatus for preventing the exposure of a photographicoriginal exhibiting an excessively high or excessively low transmittanceto radiation, said apparatus comprising: a. means for directingradiation through said photographic original; b. first and secondphotosensitive means responsive to the intensity of radiationtransmitted by first and second areas of said photographic original forproducing first and second signals; c. means for providing a firstreference signal having a maximum level indicative of the maximumtransmittance of a photographic original that can be successfullyprinted; d. means for providing a second reference signal having aminimum level indicative of the minimum transmittance of a photographicoriginal that can be successfully printed; e. means responsive to thefirst reference signal and the first and second signals for producing afirst unprinTable original signal when the levels of the first andsecond signals exceed the maximum level of the first reference signal;f. means responsive to the second reference signal and the first andsecond signals for producing a second unprintable original signal whensaid minimum level of the second reference signal exceeds the level ofthe first and second signals; and g. means responsive to the first andsecond unprintable original signals for preventing the printing of saidphotographic original.
 15. The apparatus of claim 14 wherein said firstreference signal providing means further comprises means for varying themaximum level of the first reference signal and said second referencesignal providing means further comprises means for varying the minimumlevel of the second reference signal.
 16. The apparatus of claim 14wherein said first and second photosensitive means further comprises: a.first and second photosensitive elements each having first and secondterminals, said first terminals being commonly connected to a firstvoltage source, first and second resistance elements, each respectivelyconnecting said second terminal to a second voltage source, each of saidphotosensitive elements responding to radiation transmitted by eachrespective area of said photographic original to produce the firstsignal and the second signal at the respective second terminals of saidfirst and second photosensitive elements; b. first means connected tosaid second terminals of said first and second photosensitive elementsand responsive to the first and second signals for producing a firstoutput signal having a level representative of the maximum level of thefirst and second signals; and c. second means connected to said secondterminals of said first and second elements and responsive to the firstand second signals for producing a second output signal having a levelrepresentative of the minimum level of the first and second signals. 17.The apparatus of claim 16 wherein said first unprintable original signalproducing means is responsive to the first output signal and the firstreference signal and wherein said second unprintable original signalproducing means is responsive to the second output signal and the secondreference signal.
 18. In a photographic printer, wherein successivephotographic original filmstrips are attached together by splices,apparatus for preventing the exposure of said splices and of unprintablephotographic originals exhibiting an excessively high or excessively lowtransmittance to radiation, said apparatus comprising: a. means fordirecting radiation through the photographic originals; b. first andsecond photosensitive means responsive to the intensity of radiationtransmitted by first and second respective areas of said photographicoriginal for producing first and second signals having levels dependentupon the radiation intensities transmitted by said first and secondareas; c. means for providing a first reference signal having a maximumlevel indicative of the maximum transmittance of a photographic originalthat can be successfully printed; d. means for providing a secondreference signal having a minimum level indicative of the minimumtransmittance of a photographic original that can be successfullyprinted; e. means responsive to the first reference signal and the firstand second signals for producing a first unprintable original signalwhen the levels of the first and second signals exceed the maximum levelof the first reference signal; f. means responsive to the secondreference signal and the first and second signals for producing a secondunprintable original signal when said minimum level of the secondreference signal exceeds the levels of the first and second signals; g.means responsive to the first and second unprintable original signal forpreventing the printing of said photographic original; h. thirdphotosensitive means located with respect to said raDiation transmittingmeans and said photographic original filmstrip for producing a splicesignal when a splice attaching successive photographic originalfilmstrips prevents the transmission of radiation through saidphotographic original filmstrip and upon said second photosensitivemeans; and i. means responsive to said splice signal for preventing theprinting of the splice areas of said attached successive photographicoriginal filmstrips.
 19. The apparatus of claim 18 wherein said thirdphotosensitive means is responsive to a predetermined radiation spectrumof the radiation transmitting means and wherein said splice comprisesmeans for preventing the transmission of said predetermined spectrum ofradiation to said third radiation sensitive means.
 20. In a photographicprinter, apparatus for controlling the exposure of a photographicoriginal exhibiting an imbalance in density modulation between first andsecond areas of the photographic original and for preventing theexposure of a photographic original exhibiting an excessively high orexcessively low transmittance to radiation in both the first and thesecond areas, said apparatus comprising: a. means for directingradiation through said photographic original; b. first and secondphotosensitive means responsive to the intensity of radiationtransmitted by first and second respective areas of said photographicoriginal for producing first and second signals having levels dependentupon the density modulation of each respective area of said photographicoriginal; c. means for producing a first reference signal having amaximum level indicative of the maximum transmittance of a photographicoriginal that can be successfully printed; d. means for producing asecond reference signal having a minimum level indicative of the minimumtransmittance of a photographic original that can be successfullyprinted; e. means responsive to the first reference signal and the firstand second signals for producing a first unprintable original signalwhen the levels of both the first and the second signal exceed themaximum level of the first reference signal; f. means responsive to thesecond reference signal and the first and second signals for producing asecond unprintable original signal when said minimum level of the secondreference signal exceeds the levels of both the first and the secondsignal; g. means responsive to the first and second unprintable originalsignal for preventing the printing of said photographic original; and h.means responsive to the absence of the first and second unprintableoriginal signals and responsive to an imbalance in the amplitudes of thefirst and second signals for producing an exposure correction signal.21. The apparatus of claim 10 wherein the exposure correction signalproducing means further comprises: a. first means for producing a firstcorrection signal when the level of the first signal exceeds the levelof the second signal; b. second means for producing a second correctionsignal when the level of the second signal exceeds the level of thefirst signal; and c. third means for producing a third correction signalwhen the levels of the first and second signals are approximately equal.22. In a photographic printer, apparatus for providing an exposurecorrection signal for a photographic original exhibiting an imbalance indensity modulation in first and second areas of the photographicoriginal, said apparatus comprising: a. means for directing radiationthrough said photographic original; b. first and second photosensitivemeans responsive to the intensity of radiation transmitted by first andsecond respective areas of said photographic original for producingfirst and second signals each having a level dependent upon the densitymodulation of each respective area of said photographic original; c.means responsive to the amplitude of said first and said second signalfor providing an unprintable photograpHic original signal when saidlevels indicate that both the first and second areas of the photographicoriginal are unprintable; d. means responsive to the unprintablephotographic original signal for preventing the exposure of saidphotographic original in said photographic printer; and e. meansoperative in the absence of an unprintable photographic original signaland responsive to the levels of said first and second signals forproviding an exposure correction signal dependent upon the degree ofimbalance in the levels of the first and second signals.
 23. Theapparatus of claim 22 wherein said exposure correction signal providingmeans further comprises: a. first means for producing a first exposurecorrection signal when the level of the first signal exceeds the levelof the second signal; b. second means for producing a second exposurecorrection signal when the level of the second signal exceeds the levelof the first signal; and c. third means for producing a third exposurecorrection signal when the levels of the first and second signals areapproximately equal.
 24. A method of photographic printing, whereinphotographic original filmstrips are attached together by splices andadvanced through an exposure station, said method comprising the stepsof: a. directing radiation through first and second areas of eachphotographic original; b. sensing the intensity of the radiationtransmitted by said first and second areas of the photographic original;c. comparing the sensed radiation intensity levels transmitted by saidfirst and second areas with reference radiation intensity levels; d.advancing originals exhibiting radiation transmittance levels in thefirst and second areas of the photographic original frames that areexcessively high or excessively low in comparison to the referenceradiation intensity levels through the exposure station of thephotographic printer, without printing such original frames; e.detecting splices attaching photographic original filmstrips; f.advancing detected splices through said exposure station of saidphotographic printer without printing spliced areas; g. comparing theradiation intensity levels of the radiation transmitted by the first andsecond areas and providing an exposure correction signal in response tothe degree of difference between the radiation intensity levels; h.advancing printable photographic originals into said exposure station ofsaid photographic printer; and i. controlling the exposure of saidphotographic original frame in accordance with the exposure correctionsignal.